168 resultados para morphological difference


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Background: Mandatory fortification of grain products with folic acid was introduced recently in the United States, a policy expected to result in a mean additional intake of 100 mu g/d. One way of predicting the effectiveness of this measure is to determine the effect of removing a similar amount of folic acid as fortified food from the diets of young women who had been electively exposed to chronic fortification.

Objective: The objective was to examine the effect on folate status of foods fortified with low amounts of folic acid.

Design: We investigated the changes in dietary intakes and in red blood cell and serum concentrations of folate in response to removing folic acid-fortified foods for 12 wk from the diets of women who reportedly consumed such foods at least once weekly (consumers).

Results: Consumers (n = 21) had higher total folate intakes (P = 0.002) and red blood cell folate concentrations (P = 0.023) than nonconsumers (women who consumed folic acid-fortified foods less than once weekly; n = 30). Of greater interest, a 12-wk intervention involving the exclusion of these foods resulted in a decrease in folate intake of 78 +/- 56 mu g/d (P < 0.001), which was reflected in a significant reduction in red blood cell folate concentrations (P < 0.05).

Conclusions: Cessation of eating folic acid-fortified foods resulted in removing 78 mu g folic acid/d from the diet. Over 12 wk this resulted in a lowering of red blood cell folate concentrations by 111 nmol/L (49 mu g/L). This magnitude of change in folate status in women can be anticipated as a result of the new US fortification legislation and is predicted to have a significant, although not optimal, effect in preventing neural tube defects.

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A report is presented on a split ring slot frequency selective surface (FSS) reflector whose element design and distribution allows generation of far-field difference patterns. The reflector operates by converting linearly polarised plane wave fronts into two orthogonal polarisations each with a deep null in the centre of the radiation pattern. The far-field measurement presented is in good agreement with the simulation and demonstrates a null depth of ?20dB in the centre of the radiation pattern.

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Parallel phenotypic evolution in similar environments has been well studied in evolutionary biology; however, comparatively little is known about the influence of determinism and historical contingency on the nature, extent and generality of this divergence. Taking advantage of a novel system containing multiple lake-stream stickleback populations, we examined the extent of ecological, morphological and genetic divergence between three-spined stickleback present in parapatric environments. Consistent with other lake-stream studies, we found a shift towards a deeper body and shorter gill rakers in stream fish. Morphological shifts were concurrent with changes in diet, indicated by both stable isotope and stomach contents analysis. Performing a multivariate test for shared and unique components of evolutionary response to the distance gradient from the lake, we found a strong signature of parallel adaptation. Nonparallel divergence was also present, attributable mainly to differences between river locations. We additionally found evidence of genetic substructuring across five lake-stream transitions, indicating that some level of reproductive isolation occurs between populations in these habitats. Strong correlations between pairwise measures of morphological, ecological and genetic distance between lake and stream populations supports the hypothesis that divergent natural selection between habitats drives adaptive divergence and reproductive isolation. Lake-stream stickleback divergence in Lough Neagh provides evidence for the deterministic role of selection and supports the hypothesis that parallel selection in similar environments may initiate parallel speciation.

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This paper assesses the impact of UK devolution on social housing policy in Northern Ireland from 1999 until 2011, with a particular focus on the administration from May 2007 until April 2011, the first in which the elected elements of the process functioned for the entire period. Housing is one of the responsibilities of the Minister for Social Development. Northern Ireland has had a political commitment to the provision of good quality social housing for many years, both before and after the 1998 Good Friday/ Belfast Agreement and the establishment of the Northern Ireland Assembly and Executive in 1999.
The paper begins with an analysis of factors contributing to policy difference within the United Kingdom under the 1999 devolution settlement, noting that these factors may contribute either to policy convergence or divergence between the four UK jurisdictions. There follow reflections on the concept of ‘policy ownership’ in multi-level states and the benefits of this analytical approach for consideration of housing policy under UK devolution. A review of social housing policy since 1999 is followed by discussion of three key issues from the 2007-11 administration: the governance of social housing; the procurement of new social housing; and improving access to shared space and a shared future. The paper concludes that, in Northern Ireland, the 2007-11 administration marked a transition between a technocratic past and the future policy ownership of the social housing policy field by locally elected politicians. Reflections on wider implications for UK social policy, for UK devolution, and for the complex governance structures of devolved and federal states are also included.

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2013 marks 10 years since the Sexual Offences Act 2003 was passed. That Act made significant changes to the law of rape which appear now to have made very little difference to reporting, prosecution or conviction rates. This article argues that the Act has failed against its own measures because it remains enmeshed within a conceptual framework of sexual indifference in which woman continues to be constructed as man’s (defective) other. This construction both constricts the frame in which women’s sexuality can be thought and distorts the harm of rape for women. It also continues woman’s historic alienation from her own nature and denies her entitlement to a becoming in line with her own sexuate identity. Using Luce Irigaray’s critical and constructive frameworks, the article seeks to imagine how law might ‘cognize’ sexual difference and thus take the preliminary steps to a juridical environment in which women can more adequately understand and articulate the harm of rape.

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Chitons are often referred to as "living fossils" in part because they are proposed as one of the earliest-diverging groups of living molluscs, but also because the gross morphology of the polyplacophoran shell has been conserved for hundreds of millions of years. As such, the analysis of evolution and radiation within polyplacophorans is of considerable interest not only for resolving the shape of pan-molluscan phylogeny but also as model organisms for the study of character evolution. This study presents a new, rigorous cladistic analysis of the morphological characters used in taxonomic descriptions for chitons in the living suborder Lepidopleurina Thiele, 1910 (the earliest-derived living group of chitons). Shell-based characters alone entirely fail to recover any recognized subdivisions within the group, which may raise serious questions about the application of fossil data (from isolated shell valves). New analysis including characters from girdle armature and gill arrangements recovers some genera within the group but also points to the lack of monophyly within the main genus Leptochiton Gray, 1847. Additional characters from molecular data and soft anatomy, used in combination, are clearly needed to resolve questions of chiton relationships. However, the data sets currently available already provide interesting insights into the analytical power of traditional morphology as well as some knowledge about the early evolution and radiation of this group.

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Background - The study of corneal endothelium, by specular microscopy, in patients with anterior uveitis has largely been restricted to observations on the endothelial cells. In this prospective study 'keratic precipitates' (KP) in different types of uveitis were examined in different stages of the disease process and the endothelial changes occurring in the vicinity of the KP were evaluated in comparison with the endothelium of the uninvolved eye. Methods - 13 patients with active unilateral uveitis were recruited. The mean age was 42.9 years (range 20-76 years). A Tomey-1100 contact wide field specular (x10) microscope was used to capture endothelial images and KP until the resolution of uveitis. Data regarding type of uveitis, number, size, and nature of KP were recorded. Automated morphometric analysis was done for cell size, cell density and coefficient of variation, and statistical comparisons of cell size and cell density were made (Student's t test) between the endothelium in the vicinity of fresh and resolving KP, fresh KP and normal endothelium, and resolving KP and normal endothelium. Results - On specular microscopy, fresh KP were seen as dense, white glistening deposits occupying 5-10 endothelial cells in diameter and fine KP were widely distributed and were one or two endothelial cells in diameter. The KP in Posner-Schlossman syndrome had a distinct and different morphology. With clinical remission of uveitis, the KP were observed to undergo characteristic morphological changes and old KP demonstrated a large, dark halo surrounding a central white deposit and occasionally a dark shadow or a 'lacuna' replaced the site of the original KP. Endothelial blebs were noted as dark shadows or defects in the endothelial mosaic in patients with recurrent uveitis. There was significant statistical difference in the mean cell size and cell density of endothelial cells in the vicinity of fresh KP compared with normal endothelium of the opposite eye. Conclusion - This study elucidated the different specular microscopic features of KP in anterior uveitis. Distinct morphological features of large and fine KP were noted. These features underwent dramatic changes on resolution of uveitis. The endothelium was abnormal in the vicinity of KP, which returned to near normal values on resolution of uveitis.